Notices and warning – create post with custom fields

When I create a post with custom fields using save() according to the documentation, I get the following notices and warning – when WP_DEBUG is on.

Notice: Trying to get property of non-object in /my/path/wp-content/plugins/custom-field-suite/includes/api.php on line 21

Notice: Trying to get property of non-object in /my/path/wp-content/plugins/custom-field-suite/includes/api.php on line 46

Warning: Cannot modify header information - headers already sent by (output started at /my/path/wp-content/plugins/custom-field-suite/includes/api.php:21) in /my/path/wp-includes/pluggable.php on line 1121

Would be great if you could look into it. Thanks and regards, Henk Jan.

https://wordpress.org/plugins/custom-field-suite/